ZURB's Foundation is a front-end for quickly building applications and prototypes. It is similar to Twitter Bootstrap but uses Sass instead of LESS. Here you will learn the basics of the grid system, navigation, tooltips and more.
(11 minutes)

RubyGems can make it easy to add a feature to a Rails application, but it can also cause headaches down the road. Here I give some tips on researching gems to decide which one to choose, or when to do it from scratch.
(7 minutes)